When the four-man orchestra sets up in the leafy porch, the dark wood of the cello shines in the sun and so do the white shirts of the elderly musicians, busy straightening their borsalino -style hats  before the show. Sitting at a cafe, admiring a crumbling colonial church, I take a sip of my cold Bucanero beer: we are in Havana and when the Buena Vista Social Club songs start to play, our picture-perfect moment is complete. We were in Havana years ago, before we had children, and of all the places we have visited during those travel intensive years, Cuba is maybe the one we would most dearly want to show our kids.…